Fuel-injecting device for internal-combustion engines



Apr 29, 1924.

R492@ M E. H. TAR-mms FUEL INJECTING DEVICE FOR INTERNAL COMBUSTIONENGINES v2 Sheets-Sheet 1 Filed July 14 V1921 mgm pri 29 1924.

E. H. TARTRAIS FUEL INJECTING DEVICE FOR INTERNAL COMEUSTION ENGINESFiled July 14 1921 2 Sheets-Sheet 2 Eugne Henri Tartras,

mvENTOR;

lb, By /Ifl -Y c., l

Patented Apr. 29, 1924.

UNITED STATES EUGN HENRI TABTBAIS, F MAISONS-LAFFITTE, FRANCE.

FUEL-INJECTING DEVICE FOB INTEBNAL-COMBUBTION ENGINFS.

Application led July 14, 1921. Serial No. 454,808.

To all whom vit-may concern.'

Be it known that I, EUGNE HENRI TAB- mais, citizen of the FrenchRepublic, residing at Maisons-Lailitte, Seine-et-Oise, in the IiRepublic of France, have invented new and useful Improvements inFuel-Injecting Devices for Internal-Combustion Engines, of which thefollowing isi. specification.

This invention relates to an internal combustion engine employin' liquidfuel wherein the fuel is injected without requiring the use ofcompressed air, according to what is termed thesolid injection method. v

Apparatus are already known for effecting the injection of liquid fuelinto these engines, such devices comprising a pump whose piston andadmission valve are controlled -by cams. the admission and exhaustvalves opening outwardly, andl a valved atomizer connected with the pumpby a delivery passage.

, This invention has for its object to obviate'the various ,drawbacksarising in the operation of injectionl devices of this class, as will beset forth in detail hereunder.

The invention consists in providing a check valve opening towards theatomizer and disposed between the latter and the discharge valve of thepump, a very small ori- 30 lice affording a constant communicationbetween the pump and the delivery passage.

Other features of the invention will be further described.

The accompanying drawing shows by way vention.

Fig. v1 is a sectional view of an injection pump and the upper part ofthe combustion chamber of an engine provided with the improvementsaccording to the invention.

Figs. 2 and 3 are detail views in side and -end elevation of thedischarge valve provided with a groove according to the invention.

Fig. 4 is a horizontal section of the body of the pump on the axis ofthe discharge valve showing the use of a needle valve.

Fig. '5 is a sectional view of a modified form of the check valvedisposed upon the atomizer.

a indicates the chamber of the fuel pump and b the frame thereof. As iswell known in the case of this class of injecting devices for liquidfuel, when the motor piston `is near the interior dead point, the pistonc of of example various embodiments of this in the pump, which is actedupon by the cam d having a quick-motion ramp, will deliver the requisitequantity of fuel, and the latter is caused to pass through the dischargevalve 6 of the pum and to lift the automatic valve 7 forming a part ofthe atomizer e. The fuel in the form of very fine drops thus enters thecombustion cham- .ber f `of the en 'ne cylinder wherein a high pressureprevai s at this time.

Between the pump and the atomizer is necessarily provided a pipe of somelength becomes reduced. The fuel which is introduced at the wrong timeis therefore used under very defective conditions. A

-This drawback is obviated either as a whole or in part by the presentinvention, wherein a check valve 1 opening towards the atomizer isdisposed between the latter and the discharge valve 6 of the pump and inimmediate proximityv to the atomizer, an orifice of very small size 5(Figs. 1 to 3) being used to afford during the working of vthe engine aconstant connection between the r[Iiump chamber a and the delivery pipe4, his orifice 5 is preferably constituted by a small notch or grooveformed in the valve 6 itself.

Taking into consideration the moment when the injection has just beencompleted, it is observed that the check valve 1 is about to close underthe action of the sprin 16. At a given moment, taking account o? thetime occupied in this closingrepresentin a few degrees of rotation ofthe crankshaf since the valve has a very light weight-*the cam 2 willbegin to o n the admission valve 3l of the ump. 'Fleiereupon thefuelcompressed in t e pipe 4 will expand, and the quantity corresponding tothisexg) sion will pass through lthe oove 5 o the discharge valve 6 and'wil `return to the suction end.

The portion of the passage v8 situated between the check valve 1 and theatomizer valve 7 will thus remain under pressure as is'necessary toprevent the formation of vapor under the action ofthe heat transmittedby the engine. The fuel contained in the pipe 4 being out of contactwith the heated portions need not be maintained under pressure. Byreason of the pressure remaming in the space 8, it is observed that thedrawback arisine from a prolonged in.- jection is not entirely overcome,but it will be remarked that the volume 8 is or may be very small. Inpractice it will be given the tenth or the twentieth part of the volumeof the pipe 4. In this manner, a considerable improvement will now havebeen made. However, means adapted to obviate the slight remainingdrawback will be set forth hereunder.

The groove 5 has a very small cross-section, and for this reason it isfound preferable to make use of a groove in the valve in preference toan orifice which is subject to clogging. The said groove is made ofsmall size for two reasons, firstly, it is required to oppose as much aspossible the output of fuel in back movement in order to prevent animpact or ram action which might set up cavities or pockets therein. andsecondly, it is especially required to be able to effect the priming ofthe pump. To carry out this latter operation, the coupling member 9 isunscrewed by several turns to permit the air and then the fuel to escapefreely through orifices such as 10. The pump is actuated by any suitablemeans, for instance by hand operation of the motor with the relief cockopen. By reason of the small size of the groove 5 compared with that ofthe admission valve 3, the pump may be operated without any otherpressure than what is represented by the height X of the liquid, inspite of the presence of the groove 5. When all the air has beenexpelled and the liquid fuel is seen to spout freely from the apertures10, the coupling member 9 is screwed tight without stopping the engine,and the entire installation is now in working order.

It has already been remarked that the pump return orifice 5 should havean extremely small size chiefly in order to enable the priming operationto be effected by the use of the perforated nut 9, and that it ispreferable 1n this case to form a groove upon the valve 6 rather than anaperture in the said valve or in the pump body, for it would be a verydifficult matter to form such an aperture under these conditions.

This consideration will however no longer hold good in the case of themodified form shown in Fig. 4 wherein 20 indicates the body of the pump,21 the pump chamber 5f proper, 22 the valve, 23 the guide piece for thevalve forming a delivery coupler, 24 and 25 two small orifices whichvare made as small as practical conditions of construction will permitand afford acommunication between the pump and the delivery pipe, theorifice 25 opening rearwardly of the valve 22; 26 a screw needle valvefor stopping the orifice 24; 27 a small packing member for thefiuid-tight working of the member 2, and 28 ythe milled head foroperating the said needle valve.

The above-mentioned device is operated in` the following manner. v Theapertures nut 9 disposed on the atomizer remains closed, and as concernsthe present purpose it has now no longer any reason to be provided withsuch aperture as 10 (Fig. 1). The needle valve 26 is closed. The pumpmay now be actuated by hand or other means, and it will operate as ifthe orifices 24, 25 did not exist. The engine may be started under theseconditions, the needle valve be ing opened only after a few momentsrunning, in order to be assured that all the air has been expelled fromthe pipe 4. It should be observed that the needle valve 26 is used notoly for opening and closing the passage 24, 25.-', but also for anexperimental adjustment of the fiow section which should be sufficientlysmall for the reason above stated and likewise for the following reason.At the moment of the opening of the admission valve 3 which takes placemechanically in the u ward direction or outwardly of the body o thepump, the movement of the head of the valve produces a slight vacuum inthe said body of the pump, ,and this may give rise to gas bubbles, butthese latter, should any such occur, are then expelled by reason of theclosing movement of the valve. To carry this out. it is naesary that.they should be situated at. the upper part, and therefore no such gasbubbles should be formed in the piping. The means of communication ismade small either by the use of the groove 5 or the needle valve 26,whereby the, said piping is not affected by the said vacuum, and shouldany cavities or pockets be produced these will be limited to the placewherein the variation in volume shall occur, that is, to the regionsituated upon the valve head 3 itself.

It might. be su posed that the above-mentioned effect cou d no longer beproduced, since. in fact during lthe lift of the valve 3, the fuelarriving from the piping is caused to flow towards the pump body whileexpanding. This is only true to a certain extent, for the expansion ofthe fuel is extremely rapid and only occupies 'the very first moments ofthe phase of the valve lifting, or perhaps one-twentieth of the totallift, even at the highest. running speeds, this being given as anapproximate order of magnitude, The benefit obtained is thereforesubstantially negligible for the present purpose, but for anotherpurpose this is not altogether true. The formation of cavities mayresult not only from the vacuum itself but also from the shock upon thevalve at the moment of opening. It is not possible to open a valve inany practical mechanism except by a sli ht shock, even though this maybe reduce by the proper design of the cam profile. This shock willproduce a pocket, but at this precise moment the back flow of the fuelwill no doubt aid in o'pposing its formation.

Mention has alread been made of a disposition for obviating the slightloss occasioned bythe pressure remaining at the end of the injection inthe space 8 comprised between the atomizer valve 7 and the check valvel. This loss may be reduced in practice to to 1% of the full loadconsumption. In the case of small engines, by reason of the diiculty inconstructing the device to be described hereunder and likewise the smallabsolute value of the fuel lost, this approximate result may beconsidered as satisfactory. But this 1s not the same for high powerengines, and in such cases the following device may be employed.

ln this device a second valve 12, Fig. 5, connects the space 8 with thepipe 4, but this valve opens in the contrary sense to the valve 1 and isprovided with a suitably calibrated spring which is proportionallyweaker than the spring 11 of the valve 7 with reference to the size ofthe valve heads. In this manner the fuel under pressure at 8 is enabledto partially expand in the pipe 4f until a pressure is reached such thatthe valve 7 cannot be lifted even when the cylinder is entirelyevacuated, but this pressure is still suilicient to prevent theformation of vapor, as has been herebefore indicated. The simplestmethod is to dispose this additional valve within the valve 1 as shownin Fig. wherein the valve 1 contains the small additional valve 12 witha iuted guide piece 13 and a spring 14. rlhe discharge takes placethrough the orifices 15.

l't will be observed that if this device works in the proper manner, thevalve 1 thus arranged may be disposed at any suitable point on thepiping and not necessarily in immediate proximity to the atomizer. Itmay thereforebe disposed upon the pump itself as a substitute for thedischarge valve 6.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent'is:

1. An apparatus for injecting liquid fuel into the cylinder of aninternal combustion engine comprising a pump, an inlet valve and apiston for said pump, cams operating said inlet valve and piston, anautomatic discharge valve, the inlet valve and outlet valve beingadapted to open outwardly with respect to the pump barrel, a fuelatomizer having a valve adapted to open outwardly under the fue]pressure, a discharge pipe connecting the discharge valve to theatomizer and a check valvemounted in said discharge pipe, between theatomizer and the discharge valve and in close proximity to the atomzer,said check valve opening towards the atomizer, a small orifice beingprovided to afford a constant communication in operation4 between thepump barrel and the adjacent part of the discharge pipe.

2. An apparatus for injecting liquid fuel into the cylinder of aninternal combustion engine 'comprising a pump, an inlet valve and apiston for said pump, cams operating said inlet valve and piston, anautomatic discharge valve, the inlet valve and outlet valve beingadapted to open outwardly with respect to the pump barrel, a fuelatomizer having a valve adapted to open outwardly under the fuelpressure, a discharge pipe connecting the discharge valve to theatomiZer and a check valve mounted in said discharge pipe, between theatomizer and the discharge valve and in close proximity to the atomizer,said check valve opening towards the atomiz'er, a small orifice beingprovided to aiord a constant communication in operation between the pumpbarrel and the adjacent part of the discharge pipe, a vent orificeopening to the atmosphere being provided on the discharge pipe and meansfor closing said orifice when desired.

3. An apparatus for injecting liquid fuel into the cylinder of aninternal combustion engine vcomprising a pump, an inlet valve and apiston for said pump, cams operating said inlet valve and piston, anautomatic discharge valve, the .inlet valve and outlet valve beingadapted to open outwardly with respect to the pump barrel, a fuelatomizer having a valve adapted to open outwardly under the fuelpressure, a discharge pipe connecting the discharge valve to the atom-Aizer and a check valve mountedin said discharge pipe, between theatomizer and the discharge valve and in close proximity to the atomizer,said check valve opening towards the atomizer, a small orifice beingprovided in the pump body to aord a communication between the pumpbarrel and the adjacent part of the discharge pipe yand means forcontrolling said small orilice.

4. An apparatus for injecting liquid fuel into the cylinder of aninternal combustion engine comprising a pump, an inlet valve and apiston for said pump, cams operating said inlet valve and piston, anautomatic discharge valve, the inlet valve and outlet valve beingadapted to opencutwardy with respect to the pump barrel, a fuel atomiaerhaving a valve adapted to open outwardly under the fuel pressure, adischarge pipe ico im i

connecting the discharge valve to the atomthe opposite direction to thelatter, a small -izer and a check Valve mounted in said dis- `OrificebngpI'OVded t0 afford a Constant charge pipe, between the atomizer and theCommunicaton between the Pump balflel 10 discharge valve and in closeproximity to and the agdlcent Part 0f the dlschlge 1Pe' 5 the atomizersaid check valve opening to- In testmlony Whereqf I have Slgne my wardsthe atomizer, a small auxiliary valve name t0 thls Speclcatmnmounted inthe check valve and opening in EUGNE HENRI TARTRAIS.

